1. Field of the Invention
This invention relates to a drive system for a vehicle movable accessory, and especially a drive system for an automotive vehicle outer accessory, such as an antenna, a window glass, or a sun roof.
2. Description of the Prior Art
Japanese published unexamined utility model application 57-185205 discloses a control system for a motor driven rod antenna. In this control system, when the load on an antenna drive motor exceeds a certain level, the supply of an electric current to the motor is interrupted.
Japanese published unexamined utility model application 57-198104 discloses a drive system for a motor antenna mounted on a vehicle. In this drive system, an antenna drive motor is activated in response to a signal from an associated radio receiver power switch or a signal from a relay corresponding to the radio receiver power switch. The drive motor is deactivated in response to a signal from a switch of another sound device, a signal from a vehicle key switch, or signals from relays corresponding to the switch of the sound device and the key switch.
Japanese published examined utility model application 60-42487 discloses a power antenna including a antenna drive motor and limit switches. When an antenna reaches preset positions, these limit switches act to interrupt the electric current supply to the drive motor. This power antenna also includes a timer. In the case of a failure of the limit switches, the timer restricts the duration of the motor current supply to a preset interval.
Japanese published unexamined patent application 60-43903 discloses a motor antenna drive system. In this drive system, the position of an antenna is monitored by an angular position sensor associated with the shaft of an antenna drive motor. When the monitored position of the antenna reaches a given position, the drive motor is deactivated. The given position of the antenna can be selected from the longest position, the shortest position, and a position or positions intermediate between the two limit positions.
Japanese published unexamined patent application 61-18375 discloses a vehicle power window control system. In this control system, load on a window drive motor is monitored. In cases where the window is being closed, when the monitored motor load exceeds a reference level, the drive motor is stopped and is then reversed to open the window. After that, a device included in this control system inhibits activation of the drive motor in the direction of closing the window. The inhibitory operation of this device is cancelled by rethrowing a vehicular engine ignition switch.